I have a set of dia compe vc757 breaks that are losing their stopping power on the front wheel, when I started riding the bike I could easily have the back wheel in the air but now it seems to take some time to stop fully. I assume the blocks just need replacing but I can't find any original replacements and I don't know what types of blocks are decent replacements.



Any help would be gratefully recieved.

buy some shimano pads, then.

There are several things you can do. Take a piece of medium grit sandpaper, or a paper nail file and shave the shiny glaze off the pads. Then either use hot soapy water or rubbing alchohol and clean the black residue off the rims. That should improve it. If that does not work then I reccomend buying Kool Stop pads not shimaNO. Kool Stop are far superior. They make them in a red compound that is softer used for wet or muddy conditions. I use them in the dry as well a little spongy but they will stop you. They also come in black which is a little harder but works a whole lot better than shimaNO. Also Aztec makes a surperior pad to shimaNO. You can get them direct form the factory via their website.
https://www.deltacycle.com/

Most likely, the old pads have worn through to the metal below, and are no longer useful. Sanding the metal down and re-installing them will do nothing except ruin the rims. Go buy some threaded-poast brake pads, pull the old D/C's off, and save the washers. When pads are worn out, throw them out. It doesn't pay to be cheap.
I have noticed that it's not possible to adjust the angle as much as the old pads could, but the pads are cheaper, so it's a good tradeoff. You can't find the old pads anymore because the company went out of business. I gave up on trying to find these pads last year, and now use shimano 105 pads instead.

I would think one would notice if the pads were worn down to the metal. Since, however this was not stated, information was given in order to assist based on original post. Since the Dia Compe VC 757 is a linear pull brake I doubt that shimaNO 105 pads are compatible.

Strangely enough, they are.

Well moving back to the original, the Dia Compe VC 757 brake, unless changed at the place of purchase, comes with a non cartridge brake pad.
The one's I put on my wife's bike did not come with a cartridge, and all the info I can find does not show this model coming with a cartridge pad. Looking at hte shimaNO 105 brake caliper and the pads that come with it I do not see how one could use this pad with any effectiveness.
I called Cane Creek and spoke with one of their tech guys. He said that and I am corrected, that the shiamNO 105 pad would bolt on, but your adjustability would suffer. He, as I reccomend the Kool Stop pad.

:dance: :thumbup:

Fibrax make some good replacement brake blocks. They do a neat looking cartridge system, with very high quality materials, and a lot cheaper than Shimano.

Based on personal experience, I strongly advise buying KoolStop pads instead of Shimanos. Yes, the Shimanos looked alot better on my first-generation Campy calipers, but their performance was dangerously anemic.

Unfortunately, if you ride a lot, you will be replacing koolstops every few weeks.

Shimano M system pads and their others are made of a very hard material!,they have good power in the dry if set up correctly,but in the wet is a different story, and they are extremely abrasive on the rims.. My tip, as Hunter recommends is to use Koolstop : thinline Eagle 2's,these come in a dual compound and offer powerful braking and are kind to your rims! and I think you'll agree It's easier and cheaper to replace the pads a little more often than to get a wheel rebuilt with a new rim !. P.s the Koolstops are made in the USA ! buy local product and keep an American in a job!

Dat
Check out Fibrax products at

https://www.fibrax.co.uk/

They make replacement pads for Shimano/Campy/Magura cartridges, as well as their own.
They are as good, if not better than any other brand, and cost a lot less, and any UK bike shop will stock them. I use them , and can recommend them.
Shimano pads stop well, but are notorious for eating through rims.

Has anyone tried the new salmon-coloured KoolStops that Sheldon is promoting? Are they made using a softer (i.e., better-braking, faster-wearing) compound?

By the way, I have not experienced what I would consider to be inordinately fast wear with regular black KoolStops. Sorry, Alex, I gave up my sharp-looking, aerodynamic Shimanos for klunky-looking KoolStops after I had trouble stopping my Bianchi on a 12-percent downslope. My LBS owner, who sold me both sets of pads, told me my first-generation Campy calipers are the problem -- "It's amazing how bad some of the old stuff was." Perhaps I should trade up to the higher lever advantage of modern dual-pivot sidepulls.

Go for it John.
My long reach 105 dual pivots have as much stopping power as my cantilevers, and far more control.